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JME(4) FreeBSD Kernel Interfaces Manual JME(4)
NAMEjme -- JMicron Gigabit/Fast Ethernet driver
SYNOPSIS
To compile this driver into the kernel, place the following lines in your
kernel configuration file:
devicemiibusdevicejme
Alternatively, to load the driver as a module at boot time, place the
following line in loader.conf(5):
if_jme_load="YES"
DESCRIPTION
The jme device driver provides support for JMicron JMC25x PCI Express
Gigabit Ethernet controllers and JMicron JMC26x PCI Express Fast Ethernet
controllers.
All LOMs supported by the jme driver have TCP/UDP/IP checksum offload for
both transmit and receive, TCP segmentation offload (TSO), hardware VLAN
tag stripping/insertion features, Wake On Lan (WOL) and an interrupt coa-
lescing/moderation mechanism as well as a 64-bit multicast hash filter.
The JMC25x also supports Jumbo Frames (up to 9216 bytes), which can be
configured via the interface MTU setting. Selecting an MTU larger than
1500 bytes with the ifconfig(8) utility configures the adapter to receive
and transmit Jumbo Frames.
The jme driver supports the following media types:
autoselect Enable autoselection of the media type and options. The
user can manually override the autoselected mode by adding
media options to rc.conf(5).
10baseT/UTP Set 10Mbps operation.
100baseTX Set 100Mbps (Fast Ethernet) operation.
1000baseTX Set 1000baseTX operation over twisted pair.
The jme driver supports the following media options:
full-duplex Force full duplex operation.
half-duplex Force half duplex operation.
For more information on configuring this device, see ifconfig(8).
HARDWARE
The jme device driver provides support for the following Ethernet con-
trollers:
+o JMicron JMC250 PCI Express Gigabit Ethernet controller
+o JMicron JMC251 PCI Express Gigabit Ethernet with Card Read Host con-
troller
+o JMicron JMC260 PCI Express Fast Ethernet controller
+o JMicron JMC261 PCI Express Gigabit Ethernet with Card Read Host con-
troller
LOADER TUNABLES
Tunables can be set at the loader(8) prompt before booting the kernel or
stored in loader.conf(5).
hw.jme.msi_disable
This tunable disables MSI support on the Ethernet hardware. The
default value is 0.
hw.jme.msix_disable
This tunable disables MSI-X support on the Ethernet hardware.
The default value is 0.
SYSCTL VARIABLES
The following variables are available as both sysctl(8) variables and
loader(8) tunables:
dev.jme.%d.tx_coal_to
This variable sets the maximum amount of time to delay before
sending a Tx completion interrupt, in microseconds. The accepted
range is 1 to 65535; the default is 100 (100us).
dev.jme.%d.tx_coal_pkt
This variable sets the maximum number of outgoing packets which
may be coalesced together into a single Tx completion interrupt.
The accepted range is 1 to 255; the default is 8.
dev.jme.%d.rx_coal_to
This variable sets the maximum amount of time to wait for addi-
tional packets to arrive (for possible packet coalescing) before
firing an Rx completion interrupt, in microseconds. The accepted
range is 1 to 65535; the default is 100 (100us).
dev.jme.%d.rx_coal_pkt
This variable sets the maximum number of incoming packets which
may be coalesced into a single Rx completion interrupt. The
accepted range is 1 to 255; the default is 2.
dev.jme.%d.process_limit
This variable sets the maximum number of events that will be pro-
cessed in a single batch before the handler is requeued into a
taskqueue. The accepted range is 10 to 255; the default value is
128 events. The interface does not need to be brought down and
up again before a change takes effect.
SEE ALSOaltq(4), arp(4), miibus(4), netintro(4), ng_ether(4), vlan(4),
ifconfig(8)HISTORY
The jme driver was written by Pyun YongHyeon <yongari@FreeBSD.org>. It
first appeared in FreeBSD 7.1.
CAVEATS
The jme driver tries to avoid unnecessary station address reprogramming
for controllers that use eFuse to store station address. The number of
times that eFuse can be safely reprogrammed is 16 at most. In addition,
there is no way to restore the factory default station address once the
station address has been reprogrammed via eFuse. It is highly recom-
mended not to reprogram the station address and it is the responsibility
of the administrator to store the original station address in a safe
place when station address is changed.
There are two known 1000baseT link establishment issues with JMC25x. If
the full mask revision number of JMC25x controller is less than or equal
to 4 and the link partner enabled the IEEE 802.3az Energy Efficient Eth-
ernet feature, the controller will not be able to establish a 1000baseT
link. Also, if the length of the cable is longer than 120 meters, the
controller can not establish a 1000baseT link. The known workaround for
these issues is to force manual link configuration with 100baseTX instead
of relying on auto-negotiation. The full mask revision number of con-
troller can be checked with the verbose kernel boot option. Use the
lower nibble of the chip revision number to get the full mask revision of
the controller.
FreeBSD 10.1 March 4, 2012 FreeBSD 10.1